This invention relates generally to fluid bearings, and more particularly, to fluid bearings in combination with track devices to provide a capability of moving over rough and/or discontinuous surfaces.
It is known from the prior art that very large and heavy loads may be easily moved to new locations or reoriented in specific directions by means of a device known generally as a fluid bearing. Such a bearing is shown in U.S. Pat. No. 3,513,936 to Crowley. This patent shows the use of a rubberized torus shaped device, into which is forced air under constant pressure. The torus is inflated to a maximum point, at which point air begins to seep out into the chamber formed by the torus and the surface upon which it is resting until the downward pressure of the incoming air against the surface is sufficient to raise the fluid bearing and the load off the ground. This distance is typically on the order of a few thousandths of an inch.
The efficient operation of this device, however, required a fairly continuous, smooth surface. Discontinuous surfaces and/or surfaces which contained cracks or holes caused excessive wear on the rubberized portion of the fluid bearing, resulting in frequent replacement, or caused an excessive amount of air consumption from the pressurized air source. Furthermore, very rough surfaces and/or large discontinuities were impossible to negotiate using the prior art system of fluid bearings. Moreover, it was difficult using the prior art system, to negotiate sloping surfaces, and to maintain a high degree of directional control.
Several attempts have been made to solve the above mentioned problems, one such attempt being illustrated by the patent to Burtin, U.S. Pat. No. 3,261,418, which utilized an air cushion device in combination with a track. The particular belt used in this application was a flat, flexible, rubberized belt well known in the prior art for use in other track devices. Another example of such a belted device is shown in the patent to Eggington, U.S. Pat. No. 3,331,461. It has been found, however, that the use of such a belt has limited advantages over the prior art system, as cracks and/or other discontinuities in the surface of the floor upon which the track the belt was riding still caused the combination device to lose large quantities of air, and to cause excessive wear on the bearing surfaces themselves, although the addition of a track made a slight improvement over the prior art in each of these conditions.
Although the concept of a fluid bearing in combination with a belted track itself has advantages, it is the recognition that the combination must be so designed that the inner surface of the track remains smooth and continuous, regardless of the surface upon which the device is operating, and the accompanying implementation that distinguishes the present invention in one way from the prior art.
Furthermore, the use of combinations of fluid bearings, configured in various ways with platforms and with means for stabilizing and directing the movement of the combination track device or re-orienting the load also distinguish the present invention from the stated prior art.
In view of the above description of the background of the invention and the present significant problems in the fluid bearing art, it is an object of the present invention to provide a fluid bearing track device which has the capability of moving over rough and discontinuous surfaces.
It is another object of the present invention to provide a fluid bearing track device which will significantly reduce the wear on the rubberized fluid bearing enclosure surface.
It is a further object of the present invention to provide a very smooth surface upon which the fluid bearing itself will operate.
It is a still further object of the present invention to greatly reduce the loss of air in the forced air fluid bearing system.
Other and further objects, features and advantages of the invention will become more apparent as the description of the invention proceeds in the following paragraphs.